Timing issues with Virus TI using Output 1 and 2

[gotek]

But in this case there will be a delay caused by the soundcard latency!! ehehehhe... this problem is easily solved with live since you can set a delay for each track, even a forward playing setting...
but my question was more about the fact that even using the USB outs, it happens that after few that i am playin, stopping the audio for editing my loops then startin another time, and so on many times, well it happens that the virus goes out of time, and set itself with a certain delay, it is possible to compensate with this delay as told, on ableton live, but it makes me nuts anyway, cause this delay is not constant, its changin, after few minutes i must set a different delay to the track to make her play in perfect timing...
can it be a problem of low alimentation???